It is important for the safe operation of any vehicle that a clear, unobstructed view to the outside environment be maintained. An example of such viewing need is for the driver of an automobile. In this application, material such as the windshield, side windows, rearview mirrors, and rear windows have a surface exposed to the outside weather elements where rain, snow, ice, and other debris can accumulate. The accumulation of this debris poses a significant problem with maintaining a clear view to the outside environment.
In prior art, one method used to remove solid debris such as ice from a material surface consists of a device which blows hot air on the material's interior surface or heats the material surface by the Joule effect through metal wires attached to the material. A major drawback to these devices is that the time it takes to remove the debris is significant. Also, the field of view is obstructed with the metal wire technology.
In other prior art, another method used to remove debris such as ice and/or liquid from a material surface consists of only mounting transducer elements, which vibrate, directly onto the material surface. The transducer elements are made from piezoelectric or magnetostrictive material and electrical energy is used to make these elements vibrate. Such devices are described in U.S. Pat. Nos. 5,724,186; 5,155,625; 5,132,840; 5,148,312; 5,037,189; 5,007,722; 4,833,373; 5,136,425; 5,025,187; and 5,172,024. A major drawback of these devices is that the vibrating transducer elements mount perpendicular and directly on the material surface. Because the vibrating transducer elements are attached in this manner, the magnitude of the vibrations developed by the transducer elements cannot be changed, and in particular magnified, prior to entering into the material. This results in a design which is very inefficient because of the amount of energy required to generate the necessary vibration amplitude in the material to remove the unwanted debris. Another drawback of these devices is that the dimensions of the vibrating transducers have to be carefully chosen such that their natural vibration frequency is tuned to that of the material in order to be efficient. Additionally, some of the above referenced devices are mounted on the material surface in such a way that the field of view through the material can be highly obstructed if applied in the use of windshield or side windows for removing debris.
Further limitations and disadvantages of conventional, traditional, and proposed approaches will become apparent to one of skill in the art, through comparison of such systems and methods with the present invention as set forth in the remainder of the present application with reference to the drawings.